I have been an admin for just about every enterprise scale version control platform out there. Clearcase, Perforce, SourceSafe, Starteam, Subversion, Version Manager. Systems as small as 5 users up to 2500 across multiple continents with active/active or passive/active mirroring.
If you tell us a little bit about the size of your userbase, how many locations, and what your budget is I can help you.
Oh, also what sort of applications you are looking to control, and whether or not you need any sort of issue tracking.